132 research outputs found

    Ethnic Related Selection for an ADH Class I Variant within East Asia

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    The alcohol dehydrogenases (ADH) are widely studied enzymes and the evolution of the mammalian gene cluster encoding these enzymes is also well studied. Previous studies have shown that the ADH1B*47His allele at one of the seven genes in humans is associated with a decrease in the risk of alcoholism and the core molecular region with this allele has been selected for in some East Asian populations. As the frequency of ADH1B*47His is highest in East Asia, and very low in most of the rest of the world, we have undertaken more detailed investigation in this geographic region.Here we report new data on 30 SNPs in the ADH7 and Class I ADH region in samples of 24 populations from China and Laos. These populations cover a wide geographic region and diverse ethnicities. Combined with our previously published East Asian data for these SNPs in 8 populations, we have typed populations from all of the 6 major linguistic phyla (Altaic including Korean-Japanese and inland Altaic, Sino-Tibetan, Hmong-Mien, Austro-Asiatic, Daic, and Austronesian). The ADH1B genotyping data are strongly related to ethnicity. Only some eastern ethnic phyla or subphyla (Korean-Japanese, Han Chinese, Hmong-Mien, Daic, and Austronesian) have a high frequency of ADH1B*47His. ADH1B haplotype data clustered the populations into linguistic subphyla, and divided the subphyla into eastern and western parts. In the Hmong-Mien and Altaic populations, the extended haplotype homozygosity (EHH) and relative EHH (REHH) tests for the ADH1B core were consistent with selection for the haplotype with derived SNP alleles. In the other ethnic phyla, the core showed only a weak signal of selection at best.The selection distribution is more significantly correlated with the frequency of the derived ADH1B regulatory region polymorphism than the derived amino-acid altering allele ADH1B*47His. Thus, the real focus of selection may be the regulatory region. The obvious ethnicity-related distributions of ADH1B diversities suggest the existence of some culture-related selective forces that have acted on the ADH1B region

    Test of lepton universality in b→sℓ+ℓ−b \rightarrow s \ell^+ \ell^- decays

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    The first simultaneous test of muon-electron universality using B+→K+ℓ+ℓ−B^{+}\rightarrow K^{+}\ell^{+}\ell^{-} and B0→K∗0ℓ+ℓ−B^{0}\rightarrow K^{*0}\ell^{+}\ell^{-} decays is performed, in two ranges of the dilepton invariant-mass squared, q2q^{2}. The analysis uses beauty mesons produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb−1\mathrm{fb}^{-1}. Each of the four lepton universality measurements reported is either the first in the given q2q^{2} interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-046.html (LHCb public pages

    Measurement of lepton universality parameters in B+→K+ℓ+ℓ−B^+\to K^+\ell^+\ell^- and B0→K∗0ℓ+ℓ−B^0\to K^{*0}\ell^+\ell^- decays

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    A simultaneous analysis of the B+→K+ℓ+ℓ−B^+\to K^+\ell^+\ell^- and B0→K∗0ℓ+ℓ−B^0\to K^{*0}\ell^+\ell^- decays is performed to test muon-electron universality in two ranges of the square of the dilepton invariant mass, q2q^2. The measurement uses a sample of beauty meson decays produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 99 fb−1\text{fb}^{-1}. A sequence of multivariate selections and strict particle identification requirements produce a higher signal purity and a better statistical sensitivity per unit luminosity than previous LHCb lepton universality tests using the same decay modes. Residual backgrounds due to misidentified hadronic decays are studied using data and included in the fit model. Each of the four lepton universality measurements reported is either the first in the given q2q^2 interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-045.html (LHCb public pages

    Observation of a resonant structure near the Ds+Ds−D_s^+ D_s^- threshold in the B+→Ds+Ds−K+B^+\to D_s^+ D_s^- K^+ decay

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    An amplitude analysis of the B+→Ds+Ds−K+B^+\to D_s^+ D_s^- K^+ decay is carried out to study for the first time its intermediate resonant contributions, using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13 TeV. A near-threshold peaking structure, referred to as X(3960)X(3960), is observed in the Ds+Ds−D_s^+ D_s^- invariant-mass spectrum with significance greater than 12 standard deviations. The mass, width and the quantum numbers of the structure are measured to be 3956±5±103956\pm5\pm10 MeV, 43±13±843\pm13\pm8 MeV and JPC=0++J^{PC}=0^{++}, respectively, where the first uncertainties are statistical and the second systematic. The properties of the new structure are consistent with recent theoretical predictions for a state composed of ccˉssˉc\bar{c}s\bar{s} quarks. Evidence for an additional structure is found around 4140 MeV in the Ds+Ds−D_s^+ D_s^- invariant mass, which might be caused either by a new resonance with the 0++0^{++} assignment or by a J/ψϕ↔Ds+Ds−J/\psi \phi\leftrightarrow D_s^+ D_s^- coupled-channel effect.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-018.html (LHCb public pages

    First observation of a doubly charged tetraquark and its neutral partner

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    A combined amplitude analysis is performed for the decays B0→D‟0Ds+π−B^0 \rightarrow \overline{D}^0 D^+_s\pi^- and B+→D−Ds+π+B^+\rightarrow D^- D^+_s\pi^+, which are related by isospin symmetry. The analysis is based on data collected by the LHCb detector in proton-proton collisions at center-of-mass energies of 7, 8 and 13 TeV\,\rm{TeV}. The full data sample corresponds to an integrated luminosity of 9 fb−1\,\rm{fb^{-1}}. Two new resonant states with masses of 2.908±0.011±0.020 GeV2.908\pm0.011\pm0.020\,\rm{GeV} and widths of 0.136±0.023±0.011 GeV0.136\pm0.023\pm0.011\,\rm{GeV} are observed, which decay to Ds+π+D^+_s\pi^+ and Ds+π−D^+_s\pi^- respectively. The former state indicates the first observation of a doubly charged open-charm tetraquark state with minimal quark content [csˉudˉ][c\bar{s}u\bar{d}], and the latter state is a neutral tetraquark composed of [csˉuˉd][c\bar{s}\bar{u}d] quarks. Both states are found to have spin-parity 0+0^+, and their resonant parameters are consistent with each other, which suggests that they belong to an isospin triplet.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-026.html (LHCb public pages

    Search for CPCP violation in the phase space of D0→π−π+π0D^0 \to \pi^-\pi^+\pi^0 decays with the energy test

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    A search for CPCP violation in D0→π−π+π0D^0 \to \pi^-\pi^+\pi^0 decays is reported, using pppp collision data collected by the LHCb experiment from 2015 to 2018 corresponding to an integrated luminosity of 6fb−1fb^{-1}. An unbinned model-independent approach provides sensitivity to local CPCP violation within the two-dimensional phase space of the decay. The method is validated using the Cabibbo-favoured channel \D^0 \to \K^-\pi^+\pi^0 and background regions of the signal mode. The results are consistent with CPCP symmetry in this decay.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-005.html (LHCb public pages

    First observation and branching fraction measurement of the Λb0→Ds−p\Lambda_b^0\to D_s^- p decay

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    The first observation of the Λb0→Ds−p\Lambda_b^0\to D_s^- p decay is presented using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of s=13 TeV{\sqrt{s}=13 \,\textrm{TeV}}, corresponding to a total integrated luminosity of 6 fb−16\,\textrm{fb}^{-1}. Using the Λb0→Λc+π−\Lambda_b^0\to\Lambda_c^+\pi^- decay as the normalisation mode, the branching fraction of the Λb0→Ds−p\Lambda_b^0\to D_s^- p decay is measured to be B(Λb0→Ds−p)=(12.6±0.5±0.3±1.2)×10−6{\mathcal{B}(\Lambda_b^0\to D_s^- p)=(12.6 \pm 0.5 \pm 0.3 \pm 1.2 )\times 10^{-6}}, where the first uncertainty is statistical, the second systematic and the third due to uncertainties in the branching fractions of the Λb0→Λc+π−\Lambda_b^0\to\Lambda_c^+\pi^-, Ds−→K−K+π−D_s^- \to K^-K^+\pi^- and Λc+→pK−π+\Lambda_c^+\to p K^- \pi^+ decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-038.html (LHCb public pages

    Search for D∗(2007)0→Ό+Ό−D^{*}(2007)^0\to\mu^+\mu^- in B−→π−Ό+Ό−B^-\to\pi^-\mu^+\mu^- decays

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    The very rare D∗(2007)0→Ό+Ό−D^{*}(2007)^0\to\mu^+\mu^- decay is searched for by analysing B−→π−Ό+Ό−B^-\to\pi^-\mu^+\mu^- decays. The analysis uses a sample of beauty mesons produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb−1^{-1}. The signal signature corresponds to simultaneous peaks in the ÎŒ+Ό−\mu^+\mu^- and π−Ό+Ό−\pi^-\mu^+\mu^- invariant masses. No evidence for an excess of events over background is observed and an upper limit is set on the branching fraction of the decay at B(D∗(2007)0→Ό+Ό−)<2.6×10−8{\cal B}(D^{*}(2007)^0\to\mu^+\mu^-) < 2.6\times 10^{-8} at 90%90\% confidence level. This is the first limit on the branching fraction of D∗(2007)0→Ό+Ό−D^{*}(2007)^0\to\mu^+\mu^- decays and the most stringent limit on D∗(2007)0D^{*}(2007)^0 decays to leptonic final states. The analysis is the first search for a rare charm-meson decay exploiting production via beauty decays.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-004.html (LHCb public pages
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